Presentation on theme: "Jellyfish, Coral, Sea Anemone, and Hydroids"— Presentation transcript:
1 Jellyfish, Coral, Sea Anemone, and Hydroids Phylum CnidariaJellyfish, Coral, Sea Anemone, and Hydroids
2 Cnidarians Stinging cell animals Also Known As: Coelenterates: “Hollow Gut”Radial Symmetry: similar body parts surrounding a central axis
3 Body Plan No segments: oral and aboral sides Hydrostatic Skeleton: fill body cavity with water to remain upright.Shrink down as defenseOrganized at tissue level. (No true organs)Epidermis: outer cells (ectoderm)Gastrodermis: lines stomach (endoderm)Mesoglea: middle layer of gelatinous material; can be thick or thin.
5 DigestionFood is digested in the sac-like digestive cavity (only one opening)Extracellular and intracellular digestionExtracellular: outside of cellsIntracellular: inside of cellsWaste is expelled out of the mouth
6 Unique Features Cnidoblasts: stinging cells Inside each cell is a nematocyst, coiled thread with barb at the end.The nematocyst can be discharged by either physical or chemical stimulus.Physical- cnidocil (modified flagella) acts as a triggerContain a poisonous neurotoxin, varies by species
10 Nervous SystemNerve cells interconnect to form a nerve net
11 Life Cycle Jellyfish have separate sexes Both sexual and asexual reproductionSexual: external or internal (depending on species), sperm and egg form a zygote which grows into a swimming larva called the planula.In some cases the planula attaches to a hard substrate and develops into a polyp.
12 Life Cycle cont. The polyp resembles an upside-down jellyfish medusa. Small umbrella like medusas break off from the polyp by budding (asexual)
14 Classification of Cnidarians Class Hydrozoa- Hydra, Physalia, and ObeliaClass Scyphozoa- True JellyfishClass Cubozoa- box jellyfishClass Anthozoa- Corals and Sea Anemones
15 Class Hydrozoa Usually colonial, except Hydra Composition of colonies- 3 types1. Gastrozoid- responsible for feeding2. Gonozoids- responsible for sexual reproduction3. Dactyliozoids- responsible for defense; have numerous nematocysts.
19 Class Scyphozoa All marine; medusa is dominant life cycle Mesoglea is a large part of the body (mostly dead matter)Gastroderm have nematocysts; food may be eaten aliveMore toxic than hydrozoansWell developed sensory organs and glands- eyespot and chemoreceptors
24 Class Cubozoa Cube-like jellyfish Have four flattened, blade-like structures called pedaliaComplex eyes with lenses and retinas (no brain though)Only 16 species: Irukandji and Chironex- deadly box jellyfish. Can kill a human in minutes.
25 Irukandji: Carukia barnes One of, if not the deadliest box jellfish.2.5 cm (1 inch) in diameter
36 Corals and Coral Reefs Corals are colonial cnidarians Dominant form is the polypCoral reef is a massive structure composed of calcium carbonate built by coral polyps and the organisms that live with in themThe polyps take up calcium in the sea water and zooxanthellae, which live inside the polyp, take up CO2, which make limestone
39 Coral Reefs Found only in tropical areas Warm and clear water Shallow water- zooxanthellae require sunlight to photosynthesizeZooxanthellae are the primary producers of the coral reef
40 Coral Reef FormationFringing Reef: occurs when a seamount pierces the sea surface to form an island and provides a base on which the coral can growBarrier Reef: occurs if a seamount subsides slowly enough and the coral continues to grow upward at a rate that is not exceeded by the rising water. A lagoon is formed.Atoll- occurs if the seamount disappears below the surface and the coral reef is left as a ring.
44 Symbiosis and Cnidarians Symbiosis: literally means to live togetherMutualism: both organisms benefit from living togetherCommensalism: one organism benefits, the other is unaffectedParasitism: one organism benefits, one is harmed.
46 Sea Anemones and Clownfish Usually, fish the size of clownfish are stung and eaten by an anemoneClownfish become immune to the anemones nematocysts because of a mucus coatingThe mucus inhibits the anemone’s stingThe anemone provides protection and scraps of food for the clownfishThe clownfish lures prey into the anemone and cleans the anemoneWhat kind of relationship is this?______________
48 Corals and Zooxanthellae Zooxanthellae are dinoflagellates that are taken up by the coral polyps.Zooxanthellae contain chloroplastsCoral use the glucose made by the zooxanthellae as an energy supplementThe zooxanthellae benefit because they are protected and receive nutrients from the coral polyp.What type of relationship is this? _____________
49 Phylum Ctenophora Comb Jellies Take notes on your own sheet of paper, only write down what is underlined.
51 Ctenophora Group of 100 species Oval shaped with radial symmetry Resemble cnidarians but are NOT!Swim with 8 rows of ciliary combs (long cilia fused at the base)Cilia refract light whichcause a rainbow effect.Body length varies from a few centimeters to 2 m long.
52 HabitatExclusively marineCan be found in cold or warm water
53 Diet Carnivores Consume fish larvae and plankton Can expand stomach to eat organisms twice their size.Capture prey with two long tentacles armed with sticky cells called colloblastsA few species have nematocysts
54 Reproduction Sexual reproduction Hermaphrodites No polyp form; only medusa
60 On a sheet of paper do the following 1) Title the paper: Porifera, Cnidaria, and Ctenophora LabNumber your paper from 1-22Leave space on #11, #14 and #16 for drawings (about 5 lines)Use your Porifera Notes and Cnidaria Notes to answer the questions (answers only, don’t worry about writing the questions)